In another dire warning about the upcoming Atlantic hurricane season, the National Oceanic and Atmospheric Administration predicted Thursday that this year could see between 17 and 25 named tropical cyclones, the most it has ever forecast in May for the Atlantic Ocean.
NOAA’s forecast joins more than a dozen other recent projections from experts at universities, private companies and other government agencies that predicted a probability of 14 or more named storms this season; many were calling for well over 20.
Rick Spinrad, NOAA administrator, told a press conference on Thursday morning Agency forecasters estimate that eight to 13 of the storms listed could become hurricanes, meaning they could pack winds of at least 74 mph (119 km/h). Among those storms are four to seven major hurricanes – Category 3 or higher – with winds of at least 106 mph (170 km/h).
According to NOAA, there is an 85 percent chance of an above-normal season and a 10 percent chance of a near-normal season, with a 5 percent chance of a below-normal season. An average Atlantic hurricane season has 14 named storms, including seven hurricanes and three major hurricanes.
While it only takes one storm in a below-average season to devastate a community, conditions conducive to nearly twice the average number of storms increase the likelihood that North America will experience a tropical storm or, worse, a major hurricane.
There are 21 entries on this year’s official storm name list, from Alberto to William. If this list is exhausted, the National Weather Service moves on to a alternative list of namessomething she has only had to do twice in her history.
NOAA typically issues a May forecast, followed by an updated forecast in August. Before Thursday, NOAA’s highest May forecast was in 2010, when it predicted between 14 and 23 named storms; that year, 19 ultimately formed before the end of the season. In 2020, the May forecast called for between 13 and 19 named storms, but an updated August forecast was even higher, with 19 to 25 named storms. That season, 30 named storms were ultimately observed.
Hurricane forecasts this year are particularly bold because of the unprecedented conditions expected.
As forecasters look ahead to the official start of the season on June 1, they see a combination of circumstances that have never occurred in records dating back to the mid-1800s: record warm water temperatures in the Atlantic and the potential formation of a La Niña weather pattern.
Brian McNoldy, a researcher at the University of Miami who specializes in hurricane formation, said that without previous examples involving such conditions, forecasters trying to predict the coming season can only extrapolate from previous outliers.
Experts are concerned about rising ocean temperatures.
“I think all systems are set for a hyperactive season,” said Phil Klotzbach, a seasonal hurricane forecasting expert at Colorado State University.
The critical area of the Atlantic Ocean where hurricanes form is already unusually warm just before the season begins. Benjamin Kirtman, a professor of atmospheric sciences at the University of Miami, described earlier the conditions as “unprecedented,” “alarming” and an “out of bounds anomaly.”
Over the past century, those temperatures have been rising steadily. But last year, with an intensity that has baffled climate scientists, waters warmed even faster in a region of the Atlantic where most hurricanes form. That region, from West Africa to Central America, is warmer this year than it was before last year’s hurricane season began, producing 20 named storms.
Current Atlantic temperatures are concerning because they mean the ocean is primed to fuel any storms that form. Even if the surface suddenly cools, subsurface temperatures, which are also remarkably warmer than average, are expected to quickly warm surface temperatures.
These warmer temperatures can fuel storm formation and help sustain them. Sometimes, if no other atmospheric conditions are present to hinder a storm’s growth, it can intensify more quickly than usual, moving from one category to another in less than a day.
Combined with the rapid decline of the El Niño weather phenomenon in early May, the temperatures are increasing experts’ confidence in forecasting an unusually high number of storms this hurricane season.
The weakening of the El Niño phenomenon and the probability of a La Niña phenomenon increase confidence in the forecasts.
El Niño is caused by changes in ocean temperatures in the Pacific and affects weather patterns globally. When strong, it typically prevents storms from developing and growing. Last year, warm Atlantic Ocean temperatures dampened the effect of El Niño. If El Niño weakens, as forecasters predict, there won’t be much to shake up the season this time around.
Forecasters who specialize in the ebb and flow of El Niño, including Michelle L’Heureux of the National Weather Service’s Climate Prediction Center, are fairly confident not only that El Niño will weaken but that there is a high probability (77 percent) that La Niña will form at the height of hurricane season.
The system could have some surprises, she said, but at this point in the spring, things are shaping up as forecasters had predicted. A La Niña-type weather pattern would already have them looking at an above-average year. The possibility of a La Niña, combined with record-breaking sea surface temperatures this hurricane season, should create an environment ripe for storms to form and intensify this year.
